Volume 17, Number 13,
Issue of July 1, 1997
pp. 4921-4932
Copyright ©1997 Society for Neuroscience
Microtubule Organization and Stability in the Oligodendrocyte
Received Jan. 27, 1997; revised April 9, 1997; accepted April 11, 1997.
Katharine F. Lunn1, 2,
Peter W. Baas3, and
Ian D. Duncan1
1 Department of Medical Sciences,
2 Neuroscience Training Program, and
3 Department of Anatomy, University of Wisconsin-Madison,
Madison, Wisconsin 53706
The oligodendrocyte is the glial cell responsible for the formation
and maintenance of CNS myelin. Because the development of neuronal
morphology is known to depend on the presence of highly organized
microtubule arrays, it may be hypothesized that the properties of
microtubules influence the form and function of oligodendrocytes. The
goals of the present study were to define the physical attributes of
microtubules in oligodendrocytes maintained in vitro.
The results of electron and confocal microscopy indicate that
microtubules are present throughout the cell bodies and large and small
processes of oligodendrocytes and are rarely associated with discrete
microtubule-organizing centers. A modified "hooking" protocol
demonstrated that the polarity orientation of microtubules is uniformly
plus-end distal in small oligodendrocyte processes, compared with a
nonuniform, predominantly plus-end distal orientation in large
processes. Oligodendrocytes were exposed to the
microtubule-depolymerizing drug nocodazole to examine microtubule
stability in these cells. The results suggest that oligodendrocyte
microtubules can be resolved into at least three distinct microtubule
populations that differ in their kinetics of depolymerization in the
presence of nocodazole. These findings suggest that the properties of
the oligodendrocyte microtubule array reflect the functions of the
different regions of this highly specialized cell.
Key words:
oligodendrocyte;
myelination;
microtubule;
cytoskeleton;
microtubule polarity;
microtubule stability;
nocodazole